Several packages on CRAN provide (or relate to) interfaces between databases and R. Here is a summary, mostly in the words of the package descriptions. Remember that package names are case-sensitive.

The packages that talk about being DBI-compliant are referring to the DBI package (see below in “Other SQL”).

MySQL

dbConnect: Provides a graphical user interface to connect with databases that use MySQL.

RMySQL: The current version complies with the database interface definition as implemented in the package DBI 0.2-2.

TSMySQL: TSMySQL provides a MySQL interface for TSdbi. Comprehensive examples of all the TS* packages are provided in the vignette Guide.pdf with the TSdata package.

Oracle

RODM: This package implements an interface to Oracle Data Mining (ODM). It provides an ideal environment for rapid development of demos and proof of concept data mining studies. It facilitates the prototyping of vertical applications and makes ODM and the RDBMS environment easily accessible to statisticians and data analysts familiar with R but not fluent in SQL or familiar with the database environment.

PostgreSQL

TSPostgreSQL: TSPostgreSQL provides a PostgreSQL interface for TSdbi. Comprehensive examples of all the TS* packages are provided in the vignette Guide.pdf with the TSdata package.

SQLite

filehashSQLite: Simple key-value database using SQLite as the backend.

RSQLite: This package embeds the SQLite database engine in R and provides an interface compliant with the DBI package. The source for the SQLite engine (currently, version 3.7.14) is included.

RSQLite.extfuns: This package uses SQLite’s loadable extension feature to provide a number of additional SQL functions and aggregates.

TSSQLite: TSSQLite provides an SQLite interface for TSdbi. Comprehensive examples of all the TS* packages are provided in the vignette Guide.pdf with the TSdata package.

Other SQL

DBI: A database interface (DBI) definition for communication between R and relational database management systems. All classes in this package are virtual and need to be extended by the various R/DBMS implementations.

H2

Binary versions on CRAN

Here is a quote from CRAN:

Packages related to many database systems must be linked to the exact
version of the database system the user has installed, hence it does
not make sense to provide binaries for packages
RMySQL, ROracle, ROracleUI, TSMySQL, dbConnect
although it is possible to install such packages from sources by
install.packages('packagename', type='source')
after reading the manual 'R Installation and Administration'.